NOTES: It is not entirely clear if/when this model was called the Duo-Wind versus the Thayer, or if the two models are exactly the same. The cases look the same but the suggestion has been made that one is larger than the other. I cannot verify that claim. The available Duo-Wind advertisement shows neither "Duo-Wind" nor "Self Winding" on the dial. The avaiable Thayer ads show "Duo Wind" and "Self-Winding" on the dial at different points in time. Based on those ads, I believe this model to be a Thayer.